rouiFi:RA [sponges]. 29 



with ii SL'iTatL'd spii-ul ri<l:re with tUc- teeth j)oiiitinj^ upwards Hiji" • -- 

 (Fig. 8). ,^J^^ 



The body ot the spouire fi)rins u thick-w.dled cup, which, huw- - 

 ever, is so loosely constructed that lii^ht cuu he seen througii it. The 

 interior is divided up by four to eight vertical partitiuns radiating 

 from a central spike, 'i'he top of the cup is closed by a thin sieve- 

 j)late with perforated "quarters" corresponding tu the divisions 

 inside. A ''commensal "' zoophyte {Palijtlnxi) is always fitund 

 investing the upper end of the glass rope, and occasionally it forms 

 pits (often mistaken for oscules) on the surface of the spojige itself. 

 Unfortunately the Pahjthoa has become detached from the npj)er 

 part of tlie root-tuft of the specimen figured, but is abundant on the 

 surface of the sponge body. The Japanese deep-sea shark-fishers 

 obtain the sponge by means of hooks attached to their de.'p-.«ea lines. 

 By a curions parallel, the deep-sea shark-fishers of Portugal obtjiin a 

 nearly allied species of Hyalniiema in somewhat the same manner. 



Ldpliocalijx phUippinensis, from Cebu (in fluid. Table Cjise :i.\), 

 which forms a small compact thick-walled cup with long root-tufts, 

 furnishes a beautiful example of bud formation, buds of ;ill ages 

 being present on the specimens. 



Sub-Order II. Dictyoxixa. In this group the skeleton, even in 

 the earliest stages, forms a rigid framework constructed of the fused 

 rays of large regular six-rayed spicules. These sponges usually have 

 a vitreous, finely honeycombed appearance. The magnificent 

 A]jhroc((Ilist/'s r<(f<fiix (Fig. 1), in the centre of Case HI., is shaped 

 like a vase with a thick stem, and with large folds projecting out 

 from the walls. The very line specimen of ('honchisma rali/j-, to tlie 

 right of the former, is bowl-shaped, and with finger-like p )ckets 

 often extending down, like the "ro;)ts" of a Banyan tree, till they 

 reach the base on wliich the spougc is growing. The fossil Ventri- 

 culites common in flints from the Chalk are Dictyonine 8p mges.' 



CLASS III.— DE.M0SP0XC1.K (»U CO.M.MoN Si'().\(iKS. 

 The Common Sponges include all sponges other than the 

 Calcareous and Glass Sponges. 



Tetuactixellida (Four-Ray Si'ox«i ks). 

 The sponges of this Order are often spherical with a radiating Hinl>C*so IV. 

 structure (CranieUn, \\ . ;;), or they may form tough leathi-ry cakts [^.'^*j'^'^''^.^ 



* A later classification of Hcxactincllida l)y Prof. F. E. Schulzc is iiito 



two 8ul)-orders: (1) JTf.nistrropliuni {hwhuUun Diet i/oii inn) with hoxiistor tlosh 

 spicules, and ('I) Aini'liuliscojilioni wilh AntjiltulisLs. See fpriKlit VMc 

 Case .\, c'oluniiia (l and 7. 



lum. 



